The estimated resident population of Australia at 30 June 2005 was 20,328,600, an increase of 237,100 (1.2%) since 2004.

In 2005, approximately one third (33.3%) of Australia's population resided in New South Wales. In the 12 months to 2005 the largest and fastest growing state was Queensland with an increase of 75,900 people or 2.0%. While all states and territories increased in population, the Australian Capital Territory had the smallest increase (1,000 people or 0.3%).

The Sydney Statistical Division (SD) contained 20.9% of Australia's population, a proportion virtually unchanged since 2000 (21.2%). Brisbane was the fastest growing capital city SD in the country with an increase of 1.9% (33,300 people). The capital city SD with the largest growth was Melbourne with an increase of 41,300 people (1.1%), while Canberra had both the smallest and slowest growth over the same period (1,000 people or 0.3%).
In the following analysis only national estimates include Other Territories.MEDIAN AGE

The median age, the age at which half the population is older and half is younger, increased slightly in Australia between 2004 and 2005, from36.4 years to 36.6 years.

South Australia's median age (38.8 years) continues to be the highest of all states and territories of Australia, while the Northern Territory continues to have the lowest (30.9 years).

In 2005, children aged 0 to 14 years comprised 19.6% of Australia's population. The total number of children has declined marginally from 3,978,800 children in 2004 to 3,978,200 in 2005.

South Australia had the lowest proportion of children (18.4%), while the Northern Territory had the highest proportion (24.9%).

The SD with the highest proportion of its population aged under 15 in 2005 was Northern Territory - Bal (27.8%) and the lowest was Adelaide (SA) (17.6%).

Queensland recorded the largest and fastest increase in the number of children aged 0 to 14 between 2004 and 2005 (7,400 children or 0.9%), with the Northern Territory and Western Australia also experiencing growth in this age group. New South Wales recorded the largest decline (4,700 children or 0.4%).PERSONS AGED 15 TO 44 YEARS

In 2005, the proportion of people aged 15 to 44 years in Australia was 42.8%. The total number of people in this age group increased by 0.6% between 2004 and 2005 from 8,643,800 to 8,697,900.

The Northern Territory (49.0%) had the highest proportion of people aged 15 to 44, while Tasmania (39.3%) had the lowest proportion.

The SD with the highest proportion of people aged 15 to 44 years was Pilbara (WA) (51.1%), while the lowest was Yorke and Lower North (SA) (31.8%).
From 2004 to 2005 Queensland recorded the largest and fastest increase in this age group (25,100 people or 1.5%), while the largest decrease was in South Australia (900 people or 0.1%). PERSONS AGED 45 TO 64 YEARS

The proportion of Australia's population aged 45 to 64 years in 2005 was 24.5%. The total number of people in this age group rose from 4,864,000 in 2004 to 4,984,400 in 2005, an increase of 2.5%.

With 26.3% of its population aged 45 to 64 years, Tasmania had the highest proportion in this age group while the Northern Territory (21.4%) had the lowest.
The SD with the highest proportion of 45 to 64 year old people was Yorke and Lower North (SA) (29.6%), and the lowest was Kimberley (WA) (18.4%).

In the 12 months to June 2005, the population aged 45 to 64 years increased in all states and territories. The largest percentage increase was in Northern Territory (3.4% or 1,400 people), while the smallest percentage increase was in the Australian Capital Territory (1.4% or 1,136 people).
PERSONS AGED 65 YEARS AND OVER

In 2005, the proportion of Australia's population aged 65 years and over was 13.1%.The total number of people in this age group increased by 63,100 from 2004 to 2005, an increase of 2.4%.

South Australia had the highest proportion of people aged 65 years and over with 15.2% (234,800 people). The lowest proportion of people aged 65 years and over was in the Northern Territory (4.6%).

The SD with the highest proportion of its population aged 65 years and over was Yorke and Lower North (SA) (20.6%), followed by Wimmera (Vic) (19.3%). The smallest proportion of people aged 65 years and over were recorded in Pilbara (WA) with 2.6% (1,000 people).

PERSONS AGED 85 YEARS AND OVER
In 2005, the proportion of people aged 85 years and over in Australia was 1.5% (315,000 people). From 2004 to 2005 the total population aged 85 years and over increased by 6.6% (19,400 people). The growth in this age group is in part due to decreasing mortality rates.

South Australia had the highest proportion of people in this age group, with 1.9% of its total population. The Northern Territory (0.3%) had the lowest proportion of people aged 85 years and over.
The SDs with the largest proportion of their population aged 85 years and over were Wimmera (Vic) (2.6% or 1,300 people) and Yorke and Lower North (SA) (2.3% or 1,100 people). The smallest proportions of people aged 85 years and over were recorded in Australian Capital Territory - Bal with no population aged 85 years and over, and Pilbara (WA) with 0.3% (130 people).

SEX RATIO

In June 2005, females outnumbered males in Australia by 106,900. With 10,110,800 males and 10,217,800 females at June 2005, the nation's sex ratio (number of males per 100 females) was 99.0. The Northern Territory had the highest sex ratio in 2005 with 111.0, while Tasmania had the lowest ratio (97.4).
The SDs with the lowest sex ratios in Australia were Greater Hobart (Tas) (95.5), Central Highlands (Vic) and Adelaide (SA) (both 96.6%). The highest sex ratios were in Pilbara (WA) (123.4), North West (Qld) (116.9).The number of females aged 65 years and over in Australia (1,469,100) was 23% higher than the number of males (1,198,900) in 2005, resulting in a sex ratio of 81.6. The sex ratio declines more rapidly as age increases, with the population aged 85 years and over comprising more than twice as many females (213,200) as males (101,800), equating to a sex ratio of 47.8. The lower sex ratios for the more elderly age groups reflects the greater life expectancy of women.